Safety slow-down and stop motion for electric elevators.



D. LARSON. SAFETY SLOW-DOWN AND STOP MOTION FOR ELECTRIO ELEVATORS.

nruouron FILED MAY 18, 1909. 982,074. Patented Jan, 17, 1911.

B SHEETS-SHEET 1.

. n. LARSON. SAFETY SLOW-DOWN AND STOP MOTION FOR ELECTRIC ELEVATORS. APPLIOATION FILED MAY 18, 1909.

Patented Jan. 17, 1911.

2 SHEETS-SHEET 2.

wi/lmwooo UNITED PrglENT OFFICE.

DAVID LARSON, 0E YONKERS, NEW YORK, ASSIGNOR TO OTIS ELEVATOR COMPANY, .OF JERSEY CITY, NE\V JERSEY, A CORPORATION OF NEW JERSEY.

SAFETY SLOW-DOWN AND STOP M To all w hom it may comm: Be it'known that I, DAVID Larson, a subect of the'King of Sweden, residing at Yonhers, in the county of Westchester and State My invention relates to a safety slow-down.

and stop motion} device which is adapted to v be used in connection with electric elevators,

and one of theobjects of the invention as used in suchconnection is to provide means for slowing down the speed of the elevator car before either limit of the travel of the said car is reached.

Another object is to stop the car automatically at either limit of travel thereof without operative attention thereto.

A further object is to prevent the operation of the slowdown device unless thespeedof the elevator car is too great.

For the attainment of these ends and the 'accoinplishment of other new and useful com letely described, and claimed in the apillustrates my invention as applied to an elevator control system n connection with the objects, my invention consists in the features of novelty in the combination and arrangement of the several parts hereinafter more pen ed claims. In the accompanying drawings, Figure l operating switch thereof; Fig, .2 shows a modification of the same in connection with the reversing switches.

Limit switches as ordinarily employed at present, are located near the limits of travel the car and driving mechanism to continue to run at full speed until thelimit switch is opened, which is intended to stop the car and the operating mechanism without damage to the elevator.

i If the'elevator is heavily loaded or. a down trip, the tendency, when coming down at full speed, 18 to continue even after the lnnit switch has been opened, and it there is not sufficient free travel left for the car to stop,

itwill strike the bottom at nearly full speed. thereby causing damage and injury. The same difficulty may be experienced at the top limit of travel. My invention is adapted to .do away with this threatened danger entirely, by automatically slowing down the elevator car and the operative mechanism before the limit switches are reached; if the OTION FOR ELECTRIC ELEVATORS.

Specification of Letters Patent.

r E l i i i Patented Jan. 17 1911.

Application filed May 18, 1909. Serial No. 496,810.

speed is not too high" when the slow-down positions are reached. the slow-down apparel tnswill not be required, and hence will not be operated,

Referring to Fig. 1, traction sheaves 14 are provided in conjunction with the mo tor M, and the rope 15 passes around these sheaves and over the pulleys 11, 12, suspend-- ing the elevator car C and the counterweight- \V in the ordinary way.. The motor is connected to the mains and through the main fuses F, knife switch S, operating switch P, wires 16,17, reversing switch R or R, motor leads 18, 19, to the motor M; the motor field is connected to the wires 16 and 3.7 through the field lead wires 20. 21, and

the brake B is connected directly to the motor leads 18, 19 through the wires 22, 23; the brake is therefore energized whenever the motor M is actuated or in operation.

The car switch K is of the ordinary type in which. when a hand lever .26 is turned to the left of a central position, the energizing coi ot' the reversing switch R is ener gized, and when turned to the right of the central position, the energizing coil, 24 of the other reversing switch R is energized. in the central position, neither coil 24 nor 25 is energized. the motor leads 18,- 19 are not connected to the supply mains, and the notor M receives no current.

The speed governor G is operated by the rope 2.? which is connectct l to the car C in any well known manner, and a switch :38 is arranged in any convenient way to be opened by the governor G whcnthe speed of the governor reaches a predetermined limit.

Attached to the e evator car is a projecting device 33 which is provided with an inclined PI'OJECUQH or groove 34. The

hroltcn when the levers 29, 30 are engaged.

These switch levers 29. 30 are also acted upon by coil springs 39, 40, respectively, which tend to maintain the lever contacts 3:). 36 in position against the said tixed'coiitacts 37, 38. The stops 41, 42 prevent the levers 66 suitably placed on the car C to engage from turning tOQftllZ.

The operating switch P is automatically held in place by current flowing in the coil 44, and released when the 'current ceases to flow therein. The core of the coil 14 is attached to a hand lever H which is pivotally mounted by the pin 56, andis provided with a stop 55 for limiting the fall of the lever H and the core 52 of the coil 44. The hand lever H is provided so that the operating switch P may be manually operated, when so desired. v

The car safety switch 43 and the two switches controlled by levers 29, are all in series, and the three switches in series are parallel connected with the governor switch 28. The operating switch holding coil i t is in the circuit with the said switches, so that the current passing through the coil must go through the switches too. When one of these switches is automatically opened, or the car safety switch 43 is manually opened atthe same time the governor switch 28 is open, the circuit through \the operating switch holding coil 4% is broken. These circuits are traced as follows: from the positive main through fuse F, switch S, operating switch P, wires 16 and 45; then through wire 46, governor switch 28, wire ll, to wire 51, and from wire so through wire 48, switch contacts 37, 35, wire 49, switch con tacts 38, 36, wire 50,switch d3, 'to wire 51; thence through the operating switch coil l t, wires 53, 5 1-, 17, operating switch P, manual switch S, fuse F, to the negative main. From this it is seen that the operating switch coil 14 will receive current unless both the governor switch 28, and one of the three switches in series are open at the same time. 'i hi is, the speed of the elevator car C must be sufiicient to cause the governor switch 28 to be open at the same time that one of the other switches is manually or automatically opened. This will break the circuit through the operating switch holding coil 44:, and cause the operating switch P to be automatically opened to cut ed the current supply to the motor M.

Fig. 2 shows a. similar application of my invention, with the added feature that the speed of the elevator car is arrested before the limit switches are reached, and by the operation of the latter, the driving mecha' nism and the elevator car are abruptly stopped. The reference characters employed in describing the various features of Fig. l are used to designate the same portions in Fig. 2. It is therefore deemed necessary to explain only the points of difference of the latter figure.

The circuit through the operating switch coil 44 is closed through the our safetyswitch 43 and the limit'switches 62,63, which, are mechanically opened by a device the tips 64, 6 5 of the limit switch levers (S3 and ($4 This circuit may be traced from the posltlve main through the fuse F, switch .'hP16G '*"tl U7 operating switc wnes l, Mn 01 62, wlre 6S, safety switch 43, wire 69, switch .63, wire 51, operating switch coil -l-l, wires 53, 17, operating switch P, switch S, fuse F,

to the negative main. When either limit of travel of the elevator car C is reached, the corresponding limit switch 62 or G3 is opened thereby opening the operating coil circuit, which causes the operating switch l? to open, and break all current connections to the motor M.

The breaking switch 60 is closed by current flowing in the coil 59, and the object of the said switch 60 is to effect the slow-down of the motive mechanism and the elevator car C before the operation of one of the limit switches 62 or 63. Current flowing in the magnet coil 59, also flows through the gov ernor switch 28, and the two slow-down switches 29 and 30. The two switches 29, 30 are in series, and both in parallel with the governor switch 28. These circuits are traced from the positive wire 16, through wire 01, contact 70, winding 59, to wire 45, where the circuit divides, part passing through wire 4-7, governor switch 28, wire 46 to wire 58, and the remainder passing through wire e8, contacts 37, 35, wire 49, contacts 38, 36, wires 50, 57 to wire 58, from whence itpasses to the negative wire 17. This circuit can be closed only when the operating switch I is closed, and is opened when the governor switch 28 and one of the slow-down switches 29 or 30 is open at the same time.

The reversing switches N and N are operated from the car switch K by the movement of the hand lever 26, but are prevented from operating unless the breaking switch (30 is closed. These reversing switches N, N, are provided with the auxiliary con- 'tact switches n, a, which are adapted to close a circuit through the windings of the brake B. Resistance r is provided to limit the current supplied to the brake winding in such a way that the brake B will not be applied with its full stren th unless the breaking switch is opened. Then the motor M is in operation with the reversing switch N closed, the energizing circuit through the winding of the brake B is traced from tho main lead wire 16 through wire 61, contacts 70, 71 of-the breaking switch 60, wire 72, auxiliary switch 11,, wires 74, 22, through the brake winding, thence through wires 23,

20 to the other main lead wire 17. \Vhen, however, the reversing switch N is opened by the operation of the car switch K, a circuit which includes the resistance r, is closed through the brake winding. This circuit is completed through the wire 73, and the opened, through the operating switch coil slat, the

resistance 1', instead of through the contact switch a, and wire 714-. The current so restricted by the resistance 1' that only a sufficient current flows to apply the brake B gently. "his slows down the motor M, so that when either limit switch 62 or 03 is thereby breaking the circuit thecar operator, and the speed is not, too

great, it is not necessary that the safety slow-down apparatus shall be operated.

It is to be understood that the slow-down switches may be located along the elevator hatchway at any desired place or places, so that the motion of the car may be automatically arrested if the speed is too high when the car engages a slow-down switch. The preferred location of these switches is near the limits of travel of the elevator car, but occasions ma arise where itwould be con venient or'a vantageous to employ them other places. '1 The elevator car is thus pro-- tected from the inattention of the operator and from accidental speeding of the car, that there is no danger'that the car will he traveling at too great a speed when either of the limit switches is opened.

I desire not to be limited to the exact con struction, combination and arrangement as herein set forth, as it is evident that various alterations may be made by those'skilled in the artwithout departing from the principles of my invention, but .What I claim and desire to secure by Letters Patent of the United States, is 1. In a safety device for electric elevators, the combination of two switches parallel connected, a circuit breaking device in circuit therewith operative to open the parallel connected circuit, and means whereby the said circuit breaking device'opcns only when both switches are opened,

2. In a, safety device for. an electric ele- 'vator, the combination of two switches parallel connected, and a circuit breaker operative to slow down the elevator whenboth switches. are open at the same time.

3. In an electric safety for elevators, the combinationof a plurality of switches in series, a single switch parallel connected therewith, a device in" circuit with said parfillel circuits operative to slow down the jelevator when the single switch and one of the series switches time. I

In an electric safety for elevators, the combination of switches in series, a. single switch parallel connected with the first named switches, a circuit hreakingswitch, means for automatically causing the circuit breaking switch to open only when the single switch and one of the series switches are open at the same time, and means whereby the elevator is slowed down when the circuit breaking switch is opened.

5. In a safety device for elevators, the

are open at thesame combination of a governor switch, switches in series parallel connected with the govor nor switch, an electromagnetic switch de vice in circuit with the parallel connected switches, means for causing the switch device to open only when the governor switch.

and one of the series switches is open at the same time, and means whereby the speed of the elevator is arrested when the said switch device is operated,

6. In a safety device for an elevat or, the.

comhir-iation with an elevator car, of a driving motor therefor, a governor switch auto- 1 matically operated by the elevator car to open when the speed thereof is too high, limit switches in series and parallel connected with the governor switch, a breaking switch held normally inclosed iosition by current which flows through the parallel connected circuits which is antomath cally operative to break current connect-ions l ving motor when the governor d onof the limit switches'are open on ti o device for an electric elenor switch, switches connected in series, means in connection with the elevator for automatically opening-the said switches, an electro-magnetic switch maintained in a closed position by current flowing through the governor switch or the series switches, circuit connections whereby the electro-inagnetic switch is opened only when one of the series switches and the gcvernorswitch is opei'i at the same time, and means operative to retard the rhotor when the said electroinai, etic switch. is opened.

c. in an elevator safety device, the combination with. an elevator car, of switches lo along the elevator hatchway and com nected in series, an automatic governor switch, means in connection with the elevator car for operating the series connected switches, and means whereby the elevator car will be automatically slowed down when the governor switch and any one of the series connected switches are open at the same time.

9. In an elevator safety device, the combination of an elevator car, switches adapted a or, the combination of an elevator car, a driving motor therefor, anautomatic gover- &

to be engaged by the car and located at any desired places along the elevator hatchway, an automatic governor switch, and means whereby the elevator car is automatically slowed clown near any one of the switches engaged by the car when the governor switch is open at the same time the said switches are engaged by the car.

10. The combinat' in with an elevator car, of a driving motor therefor, slow-down switches, limit switches opera ive to stop the motor, an automatic governor switch, and means associated with the slow-down and governor switches whereby the motion of the elevator car is automatically arrested when the speed is too high, before the limitswitches are operated to stop the motor and the elevator car.

11. he combination with an elevator car, of a driving motor therefor, slow-down switches in series, a. governor switch parallel connected therewith, limit switches, an operating switch, means for automatically opening the operating switch to stop the motor, and means for operating the slow-down and governor switches to effect a reduction in speed of the elevator car and the motor he tore the operating switch automatically opened.

12. he combination with an elevator car, of a motor for moving the car, slow-down switches and limit switches adapted to be opened by the movement of the car, an automatic governor switch pa "allel connected with the slow-down switches which are in series, a breaking switch normally held in closed position by current which also flows through the said parallel circuit, n'ieans associated with the breaking switch tor slowing down the elevator car and motor, and means for abruptly breaking the circuit connections of the motor.

13. The combination with an elcvzitorcar, ot a motor for moving the car, slow-down switches; a governor switch, breaking switch which opens when the governor switch and a slow-down switch are open. at the same time, an operating switch, reversing switches operable manually from the elevator car when the breaking switch closed. and limit switches and a car safety switch in series with the operating switch holding coil f )1 abruptly stopping the motor and the elevator car when the speed thereof is too high.

1 1:. The combination with an elevatorcar, of a motor for moving the car, slowdown. switches, a governor switch, a breaking switch which opens when the governor switch and a slow-clown switch are open the same time, an operating switch, a car switch, reversing switches normally operable from the car switch, means for causing the breaking switch automatically to open and to reduce the speed of the motor and the switch elevator car when the speed is too hi h, and means for manually or automatically opening the operating switch. 7

15. The combination with an elevator car, of a motor for moving the car, slow-down switches, a governor switch, a breaking switch which opens when the governor switch and a slow-down switch are open at the same time, means for automatically slowing down the car when the breaking switch opens, a car controllerswitch, and reversing switches operable from the controller switch.

16. The combination with an elevator car, of a motor for moving the car, slow-down switches, a governor switch, a breaking which opens when the governor switch and a slow-down switch are open at the same time, a car controllei switch, re versing switches operable from the controller switch, a brake, a resistance, and means for inserting the resistance in th'. brake winding circuit to prevent the instantaneous application of the brake at full strength when the controller switch is oper ated to open a reversing switch.

1?. The combination with an elevator car, of a motor for moving the car, slow-down lies, a governor switch, a breaking switch which opens only when the governor switch and a slow-down switch are open at the same time, reversing switches, a car switch for manually controlling the opera tion of the reversing switches, an electrically controlled brake, resistance which is in circuit with the brak winding when the breaking switch is closed, and means for shortcircuiting the resistance when a reversing switch is closed.

18. The combination with an elevator car, of a motor for operating the car, a car com t-rol or switch, reversing switches operated by the movement of the controller-switch, an auxiliary contact switch in connection with each reversing switch and simultaneously operable therewith, an electrically operated brake, resistance adapted to be inserted in the brake winding circuit, and means wheret closing of a reversing switch shortits the resistance thereby energizing the e to release the motor.

19. The combination of an elevator car, an operating motor therefor, slow-clown vitchcs and a governor switch parallel conoperating switch, limit switches and car safety st itch in series with the operating switch holding means for 'ematically operating the parallel con-- neetcd switches to reduce the speed of the car, and means associated with the safet switch in the car for manually effecting t (5 opening of the operating switch to stop the motor at any desired time.

20. The combination of an elevator car, a. governor switch, slow-down switches con-' nected in series and in ajmiullel circuit with means associated with the elevator car for the gevernor switch, a eviee in connection with the ear for automatically opening the slow-down switches, and means whereby the I motion of the elevator ear is aulonnitieally arrested Whenever the speed thereof 1s exeeeding a predetermined limit at the same 1 time one of the slmv-(hnvn swilvhes is opened.

21. The combination of an elevator can, slow-down switches loeuledelong the elevator hoistway, a governor switch parallel connected with the slowdown switches enga ing a. slowdown switch and operative to e eat the slowing down of the elevator car when the speed. thereof is too high at any predetermined place.

In testimony whereef I have signed my name to this specification in the presence of two subscribing Witnesses.

DAVID LARSON.

itnesses ROGER XV. FLAGG, H. J. HUMEsTON. 

